This magnetic field deflects most of the galactic cosmic rays – high-energy charged particles that are incident on earth from space. The magnetic field forms the first line of defence against cosmic rays by imposing a threshold energy per unit charge. Only charged particles that have higher energy than this threshold can fall on the earth.

The analysis shows a peak in the incoming intensity of muons detected, correlated with a negative spike in the component of the magnetic field perpendicular to the ecliptic (the ecliptic is the plane of the sun’s apparent orbit). This shows that the weakening of the earth’s magnetic field because of the coronal mass ejection

There is a 32-minute lapse between the muon burst and the arrival of the interplanetary magnetic field. This is because of the time taken for the galactic cosmic rays to diffuse through the magnetised plasma.

Super storms

The largest recorded solar storm in history is the Carrington event of 1859, which disrupted telegraph lines on earth for several hours. This storm even caused Aurorae to be recorded even as far south as Florida State in the USA. If a storm of this magnitude should occur today, it would cripple all the VLSI-based communication systems, smart devices, mobile phones, computer networks and satellites, causing chaos. Since such a storm would imply a greater lowering of the threshold of cosmic rays, the incident muons would have much lower energy than the burst of muons in the present measurement, and hence, they would take longer to diffuse through. Therefore, detecting such muon bursts could serve as an early warning in the case of a superstorm.

Commenting on this, Prof. Gupta says, “A lot of research needs to be done to make it a practical proposition. However, there is a definite potential in this technique to provide an early warning of storms.”